Understanding their relationship is important when evaluating SSD performance, especially for systems that experience frequent file changes or sustained write workloads.<\/p>\n
1. TRIM and Garbage Collection Serve Different Roles<\/h2>\n
TRIM and Garbage Collection are closely related, but they are not the same operation.<\/p>\n
TRIM is a command from the host system to the SSD.<\/strong> When files are deleted or storage space is released, the operating system can use TRIM to inform the SSD that certain logical blocks no longer contain valid user data.<\/p>\n Garbage Collection is an internal SSD process.<\/strong> The SSD controller uses information about valid and invalid data to reorganize NAND flash and reclaim blocks that can be reused.<\/p>\n In simple terms:<\/p>\n TRIM tells the SSD which data is no longer needed, while Garbage Collection manages the NAND space internally.<\/strong><\/p>\n This distinction is important because NAND flash cannot simply overwrite existing data in the same way as conventional magnetic storage. Before a NAND block can be reused, existing data may need to be moved and the block erased.<\/p>\n When a user deletes a file, the operating system normally removes the file reference rather than immediately erasing the corresponding NAND cells.<\/p>\n From the SSD’s perspective, the underlying NAND data may still exist.<\/p>\n Without additional information, the SSD may continue to treat those pages as containing valid data. When the SSD later needs to reclaim the corresponding NAND block, it may have to preserve data that the user has already deleted.<\/p>\n TRIM provides a way for the operating system to communicate this information.<\/p>\n A simplified process looks like this:<\/p>\n File Deleted \u2192 Operating System Releases Logical Blocks \u2192 TRIM Notification \u2192 SSD Marks Corresponding Data as Invalid<\/strong><\/p>\n The SSD can then recognize that these pages no longer need to be retained during future NAND management operations.<\/p>\n This does not mean TRIM immediately erases the data. Instead, it gives the SSD more information about which data is no longer required.<\/p>\n Garbage Collection is performed inside the SSD and is managed primarily by the controller and firmware.<\/p>\n NAND flash stores data in pages, while erase operations are performed at the block level. Over time, a block may contain a mixture of valid and invalid pages.<\/p>\n For example, a NAND block could contain:<\/p>\n The SSD cannot simply erase individual invalid pages. Instead, the controller may need to move the remaining valid data to another location before the original block can be erased and returned to the free-block pool.<\/p>\n A simplified GC process is:<\/p>\n Identify blocks \u2192 Determine valid data \u2192 Move valid data \u2192 Erase old block \u2192 Reclaim the block for future writes<\/strong><\/p>\n The more efficiently this process is managed, the more effectively the SSD can maintain available NAND space for future operations.<\/p>\n TRIM and GC become more useful when considered as part of the same storage-management process.<\/p>\n TRIM provides information from the host side. Garbage Collection acts on that information inside the SSD.<\/p>\n For example, consider a drive containing many files. After some files are deleted, the operating system can send TRIM information to the SSD.<\/p>\n The SSD can then identify the corresponding NAND pages as no longer containing valid user data. When Garbage Collection later processes the relevant NAND blocks, it does not need to preserve those invalid pages.<\/p>\n The overall process can be simplified as:<\/p>\n File Deleted<\/strong> This cooperation can reduce unnecessary data movement and make NAND space management more efficient.<\/p>\n A new SSD usually has a large amount of immediately available NAND space. As the drive is used, data is continuously written, modified, and deleted.<\/p>\n This changes the internal state of the NAND.<\/p>\n An SSD may therefore behave differently during a long-term workload compared with a short benchmark performed on a new or lightly used drive.<\/p>\n Several factors can contribute to this difference, including:<\/p>\n For this reason, an SSD’s initial benchmark result does not necessarily describe its behavior after extended use.<\/p>\n TRIM and Garbage Collection are part of the mechanisms that help the SSD maintain usable NAND space as this state changes.<\/p>\n Available free space can have an important relationship with SSD write behavior.<\/p>\n When sufficient NAND blocks are available, the controller has more flexibility when scheduling new writes and managing existing data.<\/p>\n As the drive becomes heavily utilized, the controller may have fewer immediately available blocks and may need to perform more background data movement before completing new writes.<\/p>\n This can increase internal workload and affect write efficiency.<\/p>\n TRIM can help by identifying logical blocks that the host no longer needs. Garbage Collection can then use this information when reclaiming NAND blocks.<\/p>\n However, TRIM should not be viewed as a direct performance booster. Its benefit comes from giving the SSD better information for internal storage management.<\/p>\n The actual performance result depends on the SSD architecture, NAND configuration, controller, firmware, workload, and drive utilization.<\/p>\n Garbage Collection also has a connection with \uc4f0\uae30 \uc99d\ud3ed<\/strong>.<\/p>\n When valid data needs to be moved during block reclamation, the SSD may perform additional NAND writes beyond the data directly requested by the host system.<\/p>\n For example, if a block contains both valid and invalid pages, the valid pages may need to be copied elsewhere before the block can be erased.<\/p>\n These additional internal writes contribute to write amplification.<\/p>\n Effective TRIM information can help reduce unnecessary data movement because the SSD knows which data can be discarded instead of copied.<\/p>\n This is one reason why NAND management is not simply about raw interface bandwidth. Internal data movement can influence both performance and NAND write activity over time.<\/p>\n TRIM and Garbage Collection depend heavily on SSD firmware.<\/p>\n The controller and firmware need to manage many operations simultaneously, including:<\/p>\n The timing of these operations also matters.<\/p>\n Aggressive background management may maintain available space but consume system resources. Delaying certain operations may reduce background activity temporarily but leave more work for later.<\/p>\n Therefore, SSD firmware needs to balance performance, NAND management, power consumption, and long-term reliability.<\/p>\n The impact of these mechanisms can vary depending on how an SSD is used.<\/p>\n For a typical office PC, files may be created, modified, and deleted relatively frequently, but the overall write volume may remain moderate.<\/p>\n For systems handling large file transfers or repeated write workloads, NAND blocks can change much more rapidly. The SSD may need to perform more frequent internal data management.<\/p>\n A workload involving repeated writes, deletes, and rewrites can therefore create a very different internal NAND state from a simple sequential benchmark.<\/p>\n This is why SSD testing should consider more than one workload type.<\/p>\n Testing can include:<\/p>\n Short Benchmark<\/strong> Large File Transfer<\/strong> Repeated Write\/Delete Workload<\/strong> Long-Duration Testing<\/strong> High-Capacity Utilization Testing<\/strong> These tests provide a more complete view of how the SSD behaves over time.<\/p>\n TRIM should also be distinguished from secure erase.<\/p>\n TRIM primarily communicates that certain logical blocks are no longer required by the host. It does not necessarily mean that the NAND cells are immediately erased.<\/p>\n Garbage Collection and subsequent NAND management may reclaim those blocks later.<\/p>\n Secure erase, on the other hand, is designed for a different purpose: removing or resetting stored data according to the supported drive and system procedure.<\/p>\n Therefore, TRIM should be understood primarily as a storage-management command<\/strong>, rather than a direct data-erasure mechanism.<\/p>\n For OEM SSD projects, evaluating a drive only through a fresh-out-of-box benchmark may not provide enough information.<\/p>\n A more complete validation process can examine how the SSD behaves under different stages of use.<\/p>\n \uc608\ub97c \ub4e4\uc5b4<\/p>\n Initial Performance \u2192 Extended Workload \u2192 Data Changes \u2192 TRIM \u2192 Garbage Collection \u2192 Performance Retest<\/strong><\/p>\n Testing can focus on several areas:<\/p>\n The purpose is not simply to achieve the highest benchmark score. It is to understand whether the SSD can maintain predictable behavior under the intended application conditions.<\/p>\n TRIM and Garbage Collection should not be evaluated independently from the rest of the SSD architecture.<\/p>\n The final storage behavior is influenced by the interaction between:<\/p>\n NAND Flash + Controller + Firmware + SLC Cache + Mapping + Garbage Collection + Wear Leveling + Host Commands<\/strong><\/p>\n A change in one part of the architecture can affect the overall result.<\/p>\n For example, different NAND configurations may change available parallelism and internal management requirements. Different controller architectures may have different approaches to block management. Firmware can also change how background operations are scheduled.<\/p>\n This is why two SSDs using the same interface and similar advertised specifications can still show different behavior during long-term workloads.<\/p>\n At Oreton, we evaluate SSD performance as part of the complete storage architecture rather than focusing on a single benchmark number. Our SSD solutions can use different NAND and controller configurations depending on product requirements, including both DRAM-less and DRAM-based SSD solutions<\/strong>.<\/p>\n During product development and validation, factors such as NAND configuration, controller behavior, firmware management, performance consistency, thermal conditions, and platform compatibility all need to be considered together.<\/p>\n For OEM applications, this approach helps ensure that SSD products are evaluated not only for their initial performance, but also for their behavior during extended and changing workloads.<\/p>\n The goal is to provide storage solutions with a balance of performance, compatibility, stability, quality, and long-term consistency<\/strong>.<\/p>\n TRIM and Garbage Collection are two important parts of SSD NAND management, but neither works in isolation.<\/p>\n TRIM allows the host system to communicate which logical data is no longer needed. Garbage Collection then uses this information, together with the SSD’s internal mapping and NAND-management algorithms, to reclaim usable storage blocks.<\/p>\n Their effectiveness ultimately depends on the broader SSD architecture, including NAND flash, controller, firmware, workload, capacity utilization, and thermal conditions.<\/p>\n For this reason, long-term SSD performance should not be judged only by peak MB\/s results.<\/p>\n A better evaluation looks at how the drive manages data, maintains available NAND space, handles internal operations, and delivers consistent performance throughout its intended service life.<\/p>\n For SSD manufacturers and OEM customers, understanding these mechanisms can help create more realistic validation standards and better long-term storage solutions.<\/p>","protected":false},"excerpt":{"rendered":" SSD performance is not determined only by its interface speed, NAND flash, or controller. As an SSD is used over time, the way data is deleted, reorganized, and written back to NAND can also affect its long-term performance. Two important mechanisms involved in this process are TRIM and Garbage Collection (GC). They serve different functions,…<\/p>","protected":false},"author":3,"featured_media":4815,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4812","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"yoast_head":"\n2. How TRIM Helps the SSD Understand Unused Data<\/h2>\n
3. Garbage Collection Reorganizes NAND Flash<\/h2>\n
\n
4. TRIM and Garbage Collection Work Together<\/h2>\n
\n\u2193
\nTRIM Notification<\/strong>
\n\u2193
\nSSD Identifies Invalid Data<\/strong>
\n\u2193
\nGarbage Collection Selects NAND Blocks<\/strong>
\n\u2193
\nValid Data Is Consolidated<\/strong>
\n\u2193
\nOld Block Is Erased<\/strong>
\n\u2193
\nBlock Becomes Available for New Writes<\/strong><\/p>\n5. Why SSD Performance Can Change Over Time<\/h2>\n
\n
6. TRIM, Free Space and Sustained Write Performance<\/h2>\n
7. Garbage Collection and Write Amplification<\/h2>\n
8. The Role of SSD Firmware<\/h2>\n
\n
9. TRIM and Garbage Collection Under Different Workloads<\/h2>\n
\nMeasures initial or peak performance.<\/p>\n
\nEvaluates behavior during extended sequential writes.<\/p>\n
\nExamines NAND management under changing data conditions.<\/p>\n
\nObserves performance after the SSD has been operating for an extended period.<\/p>\n
\nEvaluates behavior when a large portion of the SSD is occupied.<\/p>\n10. TRIM Is Not the Same as Secure Erase<\/h2>\n
11. SSD Validation Should Consider Long-Term Behavior<\/h2>\n
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12. TRIM and Garbage Collection as Part of SSD Design<\/h2>\n
13. Oreton’s Approach to SSD Performance and Stability<\/h2>\n
![\"\"](\"https:\/\/oretonstorage.com\/wp-content\/uploads\/2026\/07\/2023.7.17-773x1030.png\")
<\/p>\n14. Long-Term SSD Performance Is a System-Level Result<\/h2>\n